/*
** $Id: lobject.c,v 2.113 2016/12/22 13:08:50 roberto Exp $
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/

#define lobject_c
#define LUA_CORE

#include "lprefix.h"


#include <locale.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lctype.h"
#include "ldebug.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "lvm.h"



LUAI_DDEF const TValue luaO_nilobject_ = {NILCONSTANT};


/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb(unsigned int x)
{
    int e = 0;  /* exponent */
    if (x < 8) return x;
    while (x >= (8 << 4))    /* coarse steps */
    {
        x = (x + 0xf) >> 4;  /* x = ceil(x / 16) */
        e += 4;
    }
    while (x >= (8 << 1))    /* fine steps */
    {
        x = (x + 1) >> 1;  /* x = ceil(x / 2) */
        e++;
    }
    return ((e + 1) << 3) | (cast_int(x) - 8);
}


/* converts back */
int luaO_fb2int(int x)
{
    return (x < 8) ? x : ((x & 7) + 8) << ((x >> 3) - 1);
}


/*
** Computes ceil(log2(x))
*/
int luaO_ceillog2(unsigned int x)
{
    static const lu_byte log_2[256] =    /* log_2[i] = ceil(log2(i - 1)) */
    {
        0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
    };
    int l = 0;
    x--;
    while (x >= 256)
    {
        l += 8;
        x >>= 8;
    }
    return l + log_2[x];
}


static lua_Integer intarith(lua_State *L, int op, lua_Integer v1,
                            lua_Integer v2)
{
    switch (op)
    {
    case LUA_OPADD:
        return intop(+, v1, v2);
    case LUA_OPSUB:
        return intop(-, v1, v2);
    case LUA_OPMUL:
        return intop( *, v1, v2);
    case LUA_OPMOD:
        return luaV_mod(L, v1, v2);
    case LUA_OPIDIV:
        return luaV_div(L, v1, v2);
    case LUA_OPBAND:
        return intop( &, v1, v2);
    case LUA_OPBOR:
        return intop( | , v1, v2);
    case LUA_OPBXOR:
        return intop( ^ , v1, v2);
    case LUA_OPSHL:
        return luaV_shiftl(v1, v2);
    case LUA_OPSHR:
        return luaV_shiftl(v1, -v2);
    case LUA_OPUNM:
        return intop(-, 0, v1);
    case LUA_OPBNOT:
        return intop( ^ , ~l_castS2U(0), v1);
    default:
        lua_assert(0);
        return 0;
    }
}


static lua_Number numarith(lua_State *L, int op, lua_Number v1,
                           lua_Number v2)
{
    switch (op)
    {
    case LUA_OPADD:
        return luai_numadd(L, v1, v2);
    case LUA_OPSUB:
        return luai_numsub(L, v1, v2);
    case LUA_OPMUL:
        return luai_nummul(L, v1, v2);
    case LUA_OPDIV:
        return luai_numdiv(L, v1, v2);
    case LUA_OPPOW:
        return luai_numpow(L, v1, v2);
    case LUA_OPIDIV:
        return luai_numidiv(L, v1, v2);
    case LUA_OPUNM:
        return luai_numunm(L, v1);
    case LUA_OPMOD:
    {
        lua_Number m;
        luai_nummod(L, v1, v2, m);
        return m;
    }
    default:
        lua_assert(0);
        return 0;
    }
}


void luaO_arith(lua_State *L, int op, const TValue *p1, const TValue *p2,
                TValue *res)
{
    switch (op)
    {
    case LUA_OPBAND:
    case LUA_OPBOR:
    case LUA_OPBXOR:
    case LUA_OPSHL:
    case LUA_OPSHR:
    case LUA_OPBNOT:    /* operate only on integers */
    {
        lua_Integer i1;
        lua_Integer i2;
        if (tointeger(p1, &i1) && tointeger(p2, &i2))
        {
            setivalue(res, intarith(L, op, i1, i2));
            return;
        }
        else break;  /* go to the end */
    }
    case LUA_OPDIV:
    case LUA_OPPOW:    /* operate only on floats */
    {
        lua_Number n1;
        lua_Number n2;
        if (tonumber(p1, &n1) && tonumber(p2, &n2))
        {
            setfltvalue(res, numarith(L, op, n1, n2));
            return;
        }
        else break;  /* go to the end */
    }
    default:    /* other operations */
    {
        lua_Number n1;
        lua_Number n2;
        if (ttisinteger(p1) && ttisinteger(p2))
        {
            setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
            return;
        }
        else if (tonumber(p1, &n1) && tonumber(p2, &n2))
        {
            setfltvalue(res, numarith(L, op, n1, n2));
            return;
        }
        else break;  /* go to the end */
    }
    }
    /* could not perform raw operation; try metamethod */
    lua_assert(L != NULL);  /* should not fail when folding (compile time) */
    luaT_trybinTM(L, p1, p2, res, cast(TMS, (op - LUA_OPADD) + TM_ADD));
}


int luaO_hexavalue(int c)
{
    if (lisdigit(c)) return c - '0';
    else return (ltolower(c) - 'a') + 10;
}


static int isneg(const char **s)
{
    if (**s == '-')
    {
        (*s)++;
        return 1;
    }
    else if (**s == '+')(*s)++;
    return 0;
}



/*
** {==================================================================
** Lua's implementation for 'lua_strx2number'
** ===================================================================
*/

#if !defined(lua_strx2number)

/* maximum number of significant digits to read (to avoid overflows
   even with single floats) */
#define MAXSIGDIG   30

/*
** convert an hexadecimal numeric string to a number, following
** C99 specification for 'strtod'
*/
static lua_Number lua_strx2number(const char *s, char **endptr)
{
    int dot = lua_getlocaledecpoint();
    lua_Number r = 0.0;  /* result (accumulator) */
    int sigdig = 0;  /* number of significant digits */
    int nosigdig = 0;  /* number of non-significant digits */
    int e = 0;  /* exponent correction */
    int neg;  /* 1 if number is negative */
    int hasdot = 0;  /* true after seen a dot */
    *endptr = cast(char *, s);  /* nothing is valid yet */
    while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
    neg = isneg(&s);  /* check signal */
    if (!(*s == '0' && (*(s + 1) == 'x' || *(s + 1) == 'X')))  /* check '0x' */
        return 0.0;  /* invalid format (no '0x') */
    for (s += 2; ; s++)    /* skip '0x' and read numeral */
    {
        if (*s == dot)
        {
            if (hasdot) break;  /* second dot? stop loop */
            else hasdot = 1;
        }
        else if (lisxdigit(cast_uchar(*s)))
        {
            if (sigdig == 0 && *s == '0')  /* non-significant digit (zero)? */
                nosigdig++;
            else if (++sigdig <= MAXSIGDIG)  /* can read it without overflow? */
                r = (r * cast_num(16.0)) + luaO_hexavalue(*s);
            else e++; /* too many digits; ignore, but still count for exponent */
            if (hasdot) e--;  /* decimal digit? correct exponent */
        }
        else break;  /* neither a dot nor a digit */
    }
    if (nosigdig + sigdig == 0)  /* no digits? */
        return 0.0;  /* invalid format */
    *endptr = cast(char *, s);  /* valid up to here */
    e *= 4;  /* each digit multiplies/divides value by 2^4 */
    if (*s == 'p' || *s == 'P')    /* exponent part? */
    {
        int exp1 = 0;  /* exponent value */
        int neg1;  /* exponent signal */
        s++;  /* skip 'p' */
        neg1 = isneg(&s);  /* signal */
        if (!lisdigit(cast_uchar(*s)))
            return 0.0;  /* invalid; must have at least one digit */
        while (lisdigit(cast_uchar(*s)))  /* read exponent */
            exp1 = exp1 * 10 + *(s++) - '0';
        if (neg1) exp1 = -exp1;
        e += exp1;
        *endptr = cast(char *, s);  /* valid up to here */
    }
    if (neg) r = -r;
    return l_mathop(ldexp)(r, e);
}

#endif
/* }====================================================== */


/* maximum length of a numeral */
#if !defined (L_MAXLENNUM)
#define L_MAXLENNUM 200
#endif

static const char *l_str2dloc(const char *s, lua_Number *result, int mode)
{
    char *endptr;
    *result = (mode == 'x') ? lua_strx2number(s, &endptr)  /* try to convert */
              : lua_str2number(s, &endptr);
    if (endptr == s) return NULL;  /* nothing recognized? */
    while (lisspace(cast_uchar(*endptr))) endptr++;  /* skip trailing spaces */
    return (*endptr == '\0') ? endptr : NULL;  /* OK if no trailing characters */
}


/*
** Convert string 's' to a Lua number (put in 'result'). Return NULL
** on fail or the address of the ending '\0' on success.
** 'pmode' points to (and 'mode' contains) special things in the string:
** - 'x'/'X' means an hexadecimal numeral
** - 'n'/'N' means 'inf' or 'nan' (which should be rejected)
** - '.' just optimizes the search for the common case (nothing special)
** This function accepts both the current locale or a dot as the radix
** mark. If the convertion fails, it may mean number has a dot but
** locale accepts something else. In that case, the code copies 's'
** to a buffer (because 's' is read-only), changes the dot to the
** current locale radix mark, and tries to convert again.
*/
static const char *l_str2d(const char *s, lua_Number *result)
{
    const char *endptr;
    const char *pmode = strpbrk(s, ".xXnN");
    int mode = pmode ? ltolower(cast_uchar(*pmode)) : 0;
    if (mode == 'n')  /* reject 'inf' and 'nan' */
        return NULL;
    endptr = l_str2dloc(s, result, mode);  /* try to convert */
    if (endptr == NULL)    /* failed? may be a different locale */
    {
        char buff[L_MAXLENNUM + 1];
        const char *pdot = strchr(s, '.');
        if (strlen(s) > L_MAXLENNUM || pdot == NULL)
            return NULL;  /* string too long or no dot; fail */
        strcpy(buff, s);  /* copy string to buffer */
        buff[pdot - s] = lua_getlocaledecpoint();  /* correct decimal point */
        endptr = l_str2dloc(buff, result, mode);  /* try again */
        if (endptr != NULL)
            endptr = s + (endptr - buff);  /* make relative to 's' */
    }
    return endptr;
}


#define MAXBY10     cast(lua_Unsigned, LUA_MAXINTEGER / 10)
#define MAXLASTD    cast_int(LUA_MAXINTEGER % 10)

static const char *l_str2int(const char *s, lua_Integer *result)
{
    lua_Unsigned a = 0;
    int empty = 1;
    int neg;
    while (lisspace(cast_uchar(*s))) s++;  /* skip initial spaces */
    neg = isneg(&s);
    if (s[0] == '0' &&
            (s[1] == 'x' || s[1] == 'X'))    /* hex? */
    {
        s += 2;  /* skip '0x' */
        for (; lisxdigit(cast_uchar(*s)); s++)
        {
            a = a * 16 + luaO_hexavalue(*s);
            empty = 0;
        }
    }
    else    /* decimal */
    {
        for (; lisdigit(cast_uchar(*s)); s++)
        {
            int d = *s - '0';
            if (a >= MAXBY10 && (a > MAXBY10 || d > MAXLASTD + neg))  /* overflow? */
                return NULL;  /* do not accept it (as integer) */
            a = a * 10 + d;
            empty = 0;
        }
    }
    while (lisspace(cast_uchar(*s))) s++;  /* skip trailing spaces */
    if (empty || *s != '\0') return NULL;  /* something wrong in the numeral */
    else
    {
        *result = l_castU2S((neg) ? 0u - a : a);
        return s;
    }
}


size_t luaO_str2num(const char *s, TValue *o)
{
    lua_Integer i;
    lua_Number n;
    const char *e;
    if ((e = l_str2int(s, &i)) != NULL)    /* try as an integer */
    {
        setivalue(o, i);
    }
    else if ((e = l_str2d(s, &n)) != NULL)    /* else try as a float */
    {
        setfltvalue(o, n);
    }
    else
        return 0;  /* conversion failed */
    return (e - s) + 1;  /* success; return string size */
}


int luaO_utf8esc(char *buff, unsigned long x)
{
    int n = 1;  /* number of bytes put in buffer (backwards) */
    lua_assert(x <= 0x10FFFF);
    if (x < 0x80)  /* ascii? */
        buff[UTF8BUFFSZ - 1] = cast(char, x);
    else    /* need continuation bytes */
    {
        unsigned int mfb = 0x3f;  /* maximum that fits in first byte */
        do    /* add continuation bytes */
        {
            buff[UTF8BUFFSZ - (n++)] = cast(char, 0x80 | (x & 0x3f));
            x >>= 6;  /* remove added bits */
            mfb >>= 1;  /* now there is one less bit available in first byte */
        }
        while (x > mfb);    /* still needs continuation byte? */
        buff[UTF8BUFFSZ - n] = cast(char, (~mfb << 1) | x);  /* add first byte */
    }
    return n;
}


/* maximum length of the conversion of a number to a string */
#define MAXNUMBER2STR   50


/*
** Convert a number object to a string
*/
void luaO_tostring(lua_State *L, StkId obj)
{
    char buff[MAXNUMBER2STR];
    size_t len;
    lua_assert(ttisnumber(obj));
    if (ttisinteger(obj))
        len = lua_integer2str(buff, sizeof(buff), ivalue(obj));
    else
    {
        len = lua_number2str(buff, sizeof(buff), fltvalue(obj));
#if !defined(LUA_COMPAT_FLOATSTRING)
        if (buff[strspn(buff, "-0123456789")] == '\0')    /* looks like an int? */
        {
            buff[len++] = lua_getlocaledecpoint();
            buff[len++] = '0';  /* adds '.0' to result */
        }
#endif
    }
    setsvalue2s(L, obj, luaS_newlstr(L, buff, len));
}


static void pushstr(lua_State *L, const char *str, size_t l)
{
    setsvalue2s(L, L->top, luaS_newlstr(L, str, l));
    luaD_inctop(L);
}


/*
** this function handles only '%d', '%c', '%f', '%p', and '%s'
   conventional formats, plus Lua-specific '%I' and '%U'
*/
const char *luaO_pushvfstring(lua_State *L, const char *fmt, va_list argp)
{
    int n = 0;
    for (;;)
    {
        const char *e = strchr(fmt, '%');
        if (e == NULL) break;
        pushstr(L, fmt, e - fmt);
        switch (*(e + 1))
        {
        case 's':    /* zero-terminated string */
        {
            const char *s = va_arg(argp, char *);
            if (s == NULL) s = "(null)";
            pushstr(L, s, strlen(s));
            break;
        }
        case 'c':    /* an 'int' as a character */
        {
            char buff = cast(char, va_arg(argp, int));
            if (lisprint(cast_uchar(buff)))
                pushstr(L, &buff, 1);
            else  /* non-printable character; print its code */
                luaO_pushfstring(L, "<\\%d>", cast_uchar(buff));
            break;
        }
        case 'd':    /* an 'int' */
        {
            setivalue(L->top, va_arg(argp, int));
            goto top2str;
        }
        case 'I':    /* a 'lua_Integer' */
        {
            setivalue(L->top, cast(lua_Integer, va_arg(argp, l_uacInt)));
            goto top2str;
        }
        case 'f':    /* a 'lua_Number' */
        {
            setfltvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
top2str:  /* convert the top element to a string */
            luaD_inctop(L);
            luaO_tostring(L, L->top - 1);
            break;
        }
        case 'p':    /* a pointer */
        {
            char buff[4 * sizeof(void *) + 8]; /* should be enough space for a '%p' */
            int l = l_sprintf(buff, sizeof(buff), "%p", va_arg(argp, void *));
            pushstr(L, buff, l);
            break;
        }
        case 'U':    /* an 'int' as a UTF-8 sequence */
        {
            char buff[UTF8BUFFSZ];
            int l = luaO_utf8esc(buff, cast(long, va_arg(argp, long)));
            pushstr(L, buff + UTF8BUFFSZ - l, l);
            break;
        }
        case '%':
        {
            pushstr(L, "%", 1);
            break;
        }
        default:
        {
            luaG_runerror(L, "invalid option '%%%c' to 'lua_pushfstring'",
                          *(e + 1));
        }
        }
        n += 2;
        fmt = e + 2;
    }
    luaD_checkstack(L, 1);
    pushstr(L, fmt, strlen(fmt));
    if (n > 0) luaV_concat(L, n + 1);
    return svalue(L->top - 1);
}


const char *luaO_pushfstring(lua_State *L, const char *fmt, ...)
{
    const char *msg;
    va_list argp;
    va_start(argp, fmt);
    msg = luaO_pushvfstring(L, fmt, argp);
    va_end(argp);
    return msg;
}


/* number of chars of a literal string without the ending \0 */
#define LL(x)   (sizeof(x)/sizeof(char) - 1)

#define RETS    "..."
#define PRE "[string \""
#define POS "\"]"

#define addstr(a,b,l)   ( memcpy(a,b,(l) * sizeof(char)), a += (l) )

void luaO_chunkid(char *out, const char *source, size_t bufflen)
{
    size_t l = strlen(source);
    if (*source == '=')    /* 'literal' source */
    {
        if (l <= bufflen)  /* small enough? */
            memcpy(out, source + 1, l * sizeof(char));
        else    /* truncate it */
        {
            addstr(out, source + 1, bufflen - 1);
            *out = '\0';
        }
    }
    else if (*source == '@')    /* file name */
    {
        if (l <= bufflen)  /* small enough? */
            memcpy(out, source + 1, l * sizeof(char));
        else    /* add '...' before rest of name */
        {
            addstr(out, RETS, LL(RETS));
            bufflen -= LL(RETS);
            memcpy(out, source + 1 + l - bufflen, bufflen * sizeof(char));
        }
    }
    else    /* string; format as [string "source"] */
    {
        const char *nl = strchr(source, '\n');  /* find first new line (if any) */
        addstr(out, PRE, LL(PRE));  /* add prefix */
        bufflen -= LL(PRE RETS POS) + 1;  /* save space for prefix+suffix+'\0' */
        if (l < bufflen && nl == NULL)    /* small one-line source? */
        {
            addstr(out, source, l);  /* keep it */
        }
        else
        {
            if (nl != NULL) l = nl - source;  /* stop at first newline */
            if (l > bufflen) l = bufflen;
            addstr(out, source, l);
            addstr(out, RETS, LL(RETS));
        }
        memcpy(out, POS, (LL(POS) + 1) * sizeof(char));
    }
}

